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7.9 Replace the immersion heater thermostat by carefully plugging the two male spade terminations on
the underside of the thermostat head into the corresponding terminations on the element. Ensure
the thermostat is pushed fully home.
7.10 Rewire the immersion heater in accordance with diagram 10, page 9. Refit and secure the
terminal cover.
7.11
DO NOT SWITCH ON EITHER THE BOILER OR IMMERSION HEATER UNTIL THE WATER
HEATER HAS BEEN RE-FILLED WITH WATER.
Re-commission the water heater following the Installation and commissioning instructions.
8. MAINTENANCE - DESCALING
THE WATER HEATER
8.1 Switch off and disconnect the electrical supply and shut down the boiler (indirect water heaters). Turn
off the water supply to the water heater.
8.2 Open a hot tap served by the water heater to relieve any system pressure. Empty the water heater
by opening the drain valve in the inlet pipe work.
8.3 Remove the terminal cover and disconnect wiring from the immersion heater thermostat. Remove the
immersion heater thermostat by carefully pulling outwards from the immersion heater.
8.4 Unscrew immersion heater. NOTE over time the immersion heater seal may become stuck to the
mating surface, if the seal is damaged replace with new one.
8.5 The loose scale in the base of the water heater can be removed by inserting the suction hose on a
“wet and dry” vacuum cleaner and sucking the scale out of the water heater.
8.6 Replace immersion heater by screwing into the immersion boss, take care not to over tighten.
8.7 Replace the immersion heater thermostat by carefully plugging the two male spade terminations on
the underside of the thermostat head into the corresponding terminations on the element.
8.8 Rewire the immersion heater in accordance with diagram 9, page 9. Close and secure the terminal
cover.
8.9
DO NOT SWITCH ON EITHER THE BOILER OR IMMERSION HEATER UNTIL THE WATER
HEATER HAS BEEN RE-FILLED WITH WATER.
Re-commission the water heater following the
Installation and commissioning instructions.
